PROJECT SUMMARY/ABSTRACT This innovative community-based participative research project will evaluate the effectiveness of using targeted social media (mommy blogs) to disseminate breast cancer environmental risk information to women and their relevant at-risk family members. We will seed targeted social media with relevant breast cancer risk messages adapted through user-centered design from Breast Cancer and the Environment Research Program (BCERP) toolkits, working in collaboration with established mommy bloggers as trusted sources to share key breast cancer risk information and recommendations with their audiences. Social media provides potentially powerful channels for communicating relevant health information in culturally sensitive and influential ways to key audiences (Rains & Keating, 2011; Shaw et al., 2006). This research is grounded in social network theory that describes the power of personal social networks for disseminating health information (Kim & Kreps, 2014; Valente, 2010); the diffusion of innovations model that describes how trusted sources can encourage and model adoption of health behaviors (Haider & Kreps, 2004; Rogers, 2003); Weick?s model of organizing that describes how strategic communicative interactions can reduce uncertainty and increase understanding about complex health challenges, as well as guide adaptive strategies for addressing health challenges (Kreps, 2009; Weick, 1969); and Rolland?s family system genetic illness model that illustrates the power of family communication for disseminating health risk information (Rolland & Williams, 2005).